Bionic pancreas helps control diabetes, study says

Jun. 15, 2014
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The smartphone component of the bionic pancreas system displays in an upper panel the blood sugar levels (black circles) as reported by the glucose monitor every five minutes, supplemented by fingerstick readings (red asterisks) entered by the patient over the past six hours. An adjacent lower panel shows doses of insulin (blue) or glucagon (red) automatically administered in response to blood sugar variations. / Boston University Department of Biomedical Engineering

by Liz Szabo, USA TODAY

by Liz Szabo, USA TODAY

People with type 1 diabetes who used a "bionic" pancreas were better able to control their blood sugar levels than those who monitored their levels manually, a small new study shows.

The artificial systems aren't organs and they aren't transplanted inside the body, says Steven Russell, assistant professor of medicine at Massachusetts General Hospital and co-author of the study published Sunday in The New England Journal of Medicine.

Instead, the experimental system involves three devices that are worn or carried outside the body: two pager-sized hormone pumps, connected to the body with thin tubes inserted under the skin, and a small "brick," combining an iPhone and continuous glucose monitor, to coordinate when each hormone should be delivered, says co-author Edward Damiano of the Boston University Department of Biomedical Engineering.

One pump delivers insulin - a hormone that lowers blood sugar - while the other delivers glucagon, a hormone that raises blood sugar, says Russell, whose research was presented at the American Diabetes Association Scientific Sessions in San Francisco.

Developers hope to help people better control their diabetes, as well as free diabetics from the burden of trying to compute how much insulin to inject throughout the day, Russell says. Insulin and other hormones are normally made by the pancreas. In people with type 1 diabetes, an autoimmune disease also known as juvenile diabetes, the pancreas doesn't make insulin, a hormone needed to move sugar from blood into cells, where it makes energy.

Diabetics whose blood sugar is consistently too high can experience a range of complications, from nerve damage to blindness and kidney failure. But low blood sugar levels can make people lose consciousness, says Damiano, who began working on the technology to help his 15-year-old son, who has had type 1 diabetes since infancy.

Calculating how much insulin to inject - such as before meals or exercise - is extremely complicated, Damiano says. And parents worry every time their child goes to bed, in case blood sugar levels drop dangerously while the child is asleep.

"People worry about finding their loved ones 'dead in bed,' " Damiano says. "Diabetes is relentless. It never takes a vacation."

Although many people with diabetes lead long, productive lives, managing the disease is time-consuming and complicated, Russell says.

Most people with type 1 diabetes today repeatedly prick their fingers to test their blood sugar, then calculate exactly how much insulin to inject to keep their levels in the healthy range, Damiano says. Non-diabetics typically have a fasting blood sugar level under 120 milligrams per deciliter. Studies show that diabetics can prevent many complications if they keep their average blood sugar under 154. Because regulating blood sugar is so difficult, however, people with type 1 diabetes have an average blood sugar of around 180.

Technology has made life easier for some.

About one-third of diabetics use insulin pumps, instead of giving themselves injections. Although the pumps are carried or worn outside the body, like pagers, they send hormones into the body through thin tubes, which are implanted under the skin. People still need to manually compute how much insulin they need, Russell says.

In the new study, involving 20 adults and 32 adolescents, doctors compared patients' blood sugar using the pump for five days, with their levels for five days using the bionic pancreas, which provides round-the-clock glucose monitoring.

Among adults, glucose levels using the bionic pancreas averaged 133, compared with 159 on the pump, the study says. Adults had low glucose levels about 4.1% of the time spent on the bionic pancreas, compared with 7.3% of the time using the pump.

Among adolescents, blood sugar levels averaged 138 on the bionic pancreas and 157 with the pump, according to the study, funded by the National Institutes of Health. The amount of time with low blood sugars was about the same, whether relying on the pump or bionic pancreas.

"This is a very significant and very exciting new advance," says endocrinologist Betul Hatipoglu, who treats diabetes at the Cleveland Clinic but who wasn't involved in the new study. "This gives me huge hopes that my patients can have a better life, with less burden," she says.

But Samuel Dagogo-Jack, president-elect for science and medicine at the American Diabetes Association, cautions that the study was small and lasted only five days. He says he'd like to see larger studies, lasting at least three months.

Doctors plan to begin a larger study Monday, with a definitive trial planned for 2016, Damiano says. The team is working on a system that will include a single pump capable of providing both hormones.